Antonella Rocca

Cytocompatibility evaluation of gum Arabic-coated ultra-pure boron nitride nanotubes on human cells

AIM Boron nitride nanotubes (BNNTs) are tubular nanoparticles with a structure analogous to that of carbon nanotubes, but with B and N atoms that completely replace the C atoms. Many favorable results indicate BNNTs as safe nanomaterials; however, important concerns have recently been raised about ultra-pure, long (~10 µm) BNNTs tested on several cell types. MATERIALS & METHODS Here, we propose additional experiments with the same BNNTs, but shortened (~1.5 µm) with a homogenization/sonication treatment that allows for their dispersion in gum Arabic aqueous solutions. Obtained BNNTs are tested on human endothelial and neuron-like cells with several independent biocompatibility assays. Moreover, for the first time, their strong sum-frequency generation signal is exploited to assess the cellular uptake. RESULTS & CONCLUSION Our data demonstrate no toxic effects up to concentrations of 20 µg/ml, once more confirming biosafety of BNNTs, and again highlighting that nanoparticle aspect ratio plays a key role in the biocompatibility evaluation.

Pilot in vivo investigation of cerium oxide nanoparticles as a novel anti-obesity pharmaceutical formulation

UNLABELLED Obesity is a worldwide pathological condition that strongly impairs human health, and, to date, no effective therapy against excessive fat accumulation has been found yet. Since overweight correlates with an increased oxidative stress, our aim is to investigate the antioxidant effects of cerium oxide nanoparticles (nanoceria) as a potential pharmaceutical approach for the treatment of obesity. Nanoceria were tested both in vitro and in vivo; they were proven to interfere with the adipogenic pathway by reducing the mRNA transcription of genes involved in adipogenesis, and by hindering the triglycerides accumulation in 3T3-L1 pre-adipocytes. Nanoceria, intraperitonally injected in Wistar rats, did not show appreciable toxic effects, but instead efficiently contributed in reducing the weight gain and in lowering the plasma levels of insulin, leptin, glucose and triglycerides. FROM THE CLINICAL EDITOR Obesity is now a significant problem worldwide. To date, obesity surgery remains the best treatment for weight reduction. Much research has been conducted to discover an effective pharmacological treatment against obesity. In this article, the authors continued their previous work in studying the anti-adipogenic properties of cerium oxide nanoparticles. The antioxidant effects of nanoceria were studied in in vitro and in vivo experiments. It was shown in animal model that nanoceria could reduce body weight effectively. These promising results may provide a novel treatment in the clinical setting in the future.

Barium titanate nanoparticles and hypergravity stimulation improve differentiation of mesenchymal stem cells into osteoblasts

Background Enhancement of the osteogenic potential of mesenchymal stem cells (MSCs) is highly desirable in the field of bone regeneration. This paper proposes a new approach for the improvement of osteogenesis combining hypergravity with osteoinductive nanoparticles (NPs). Materials and methods In this study, we aimed to investigate the combined effects of hypergravity and barium titanate NPs (BTNPs) on the osteogenic differentiation of rat MSCs, and the hypergravity effects on NP internalization. To obtain the hypergravity condition, we used a large-diameter centrifuge in the presence of a BTNP-doped culture medium. We analyzed cell morphology and NP internalization with immunofluorescent staining and coherent anti-Stokes Raman scattering, respectively. Moreover, cell differentiation was evaluated both at the gene level with quantitative real-time reverse-transcription polymerase chain reaction and at the protein level with Western blotting. Results Following a 20 g treatment, we found alterations in cytoskeleton conformation, cellular shape and morphology, as well as a significant increment of expression of osteoblastic markers both at the gene and protein levels, jointly pointing to a substantial increment of NP uptake. Taken together, our findings suggest a synergistic effect of hypergravity and BTNPs in the enhancement of the osteogenic differentiation of MSCs. Conclusion The obtained results could become useful in the design of new approaches in bone-tissue engineering, as well as for in vitro drug-delivery strategies where an increment of nanocarrier internalization could result in a higher drug uptake by cell and/or tissue constructs.

Folate-grafted boron nitride nanotubes: Possible exploitation in cancer therapy

Boron nitride nanotubes (BNNTs) have generated considerable interest among the scientific community because of their unique physical and chemical properties. They present good chemical inertness, high thermal stability, and optimal resistance to oxidation, that make them ideal candidates for biomedical applications, in particular as nanovectors for drug, gene and protein delivery into the cells. In this study, BNNTs were prepared through a synthesis based on a chemical vapor deposition (CVD) method, and thereafter chemically functionalized with folic acid. The obtained nanostructures have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The characterization showed efficiently functionalized BNNTs of length of about 1 μm. Furthermore, confocal laser microscopy demonstrated that our nanotubes can be fluorescently-traced under appropriate excitation. Thanks to this property, it has been possible to investigate their internalization by HeLa cells through confocal microscopy, demonstrating that the BNNT up-take clearly increases after the functionalization with folate, a result confirmed by inductively coupled plasma (ICP) assessment of boron content inside the treated cell cultures.

Cerium Oxide Nanoparticles Inhibit Adipogenesis in Rat Mesenchymal Stem Cells: Potential Therapeutic Implications

PurposeCerium oxide nanoparticles (nanoceria, NC) have extraordinary antioxidant activity that made them suitable as a therapeutic agent for several diseases where reactive oxygen species (ROS) act by impairing the normal redox balance. Among different functions, it has been proven that ROS are cellular messengers involved in the adipogenesis: we thus investigated the implication of NC administration in the potential inhibition of adipogenic differentiation of mesenchymal stem cells (MSCs) used as a model of adipogenesis.MethodsWe evaluated cytotoxic effects and adipogenic maturation of mesenchymal stem cells following in vitro NC administration, both at gene and at phenotype level.ResultsOverall, our results demonstrated that NC efficiently inhibit the maturation of MSCs toward adipocytes owing to their ability to reduce the production of the ROS necessary during adipogenesis.ConclusionsThese findings, even if preliminary, represent an important step toward the potential pharmaceutical application of NC in the treatment of obesity.

Evaluation of the effects of boron nitride nanotubes functionalized with gum arabic on the differentiation of rat mesenchymal stem cells

The use of nanostructured materials in biomedical applications has been widely investigated, in particular with the aim of using these materials to selectively carry drugs or molecules of interest to a target tissue or organ. Boron nitride nanotubes (BNNTs) functionalized with specific moieties have been demonstrated to be useful candidates for the targeted delivery of proteins, drugs and nucleic acids. We evaluated the influence of BNNTs functionalized with gum arabic on the differentiation of mesenchymal stem cells. The nanotubes were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectrometry, Raman spectrometry and dynamic light scattering. In vitro assays were performed on mesenchymal stem cells to evaluate the cytocompatibility of the functionalized BNNTs in terms of cell viability and metabolic activity. The interactions of the cells with the nanoparticles were further investigated by analyzing the conformation of the cytoskeleton. The differentiation of the mesenchymal stem cells into adipocytes and osteocytes after treatments with safe doses of BNNTs was assessed at both the gene and phenotype levels.

Pectin-coated boron nitride nanotubes: In vitro cyto-/immune-compatibility on RAW 264.7 macrophages.

BACKGROUND Boron nitride nanotubes (BNNTs) represent a new opportunity for drug delivery and clinical therapy. The present work has the objective to investigate pectin-coated BNNTs (P-BNNTs) for their biocompatibility on macrophage cultures, since these cells are among the first components of the immune system to interact with administered nanoparticles. METHODS As first step, the potential toxicity of P-BNNTs is verified in terms of proliferation, oxidative stress induction and apoptosis/necrosis phenomena. Thereafter, the modulation of immune cell response following P-BNNT exposure is evaluated at gene and protein level, in particular focusing on cytokine release. Finally, P-BNNT internalization is assessed through transmission electron microscopy and confocal microscopy. RESULTS The results proved that P-BNNTs are not toxic for macrophages up to 50 μg/ml after 24 h of incubation. The cytokine expression is not affected by P-BNNT administration both at gene and protein level. Moreover, P-BNNTs are internalized by macrophages without impairments of the cell structures. CONCLUSIONS Collected data suggest that P-BNNTs cause neither adverse effects nor inflammation processes in macrophages. GENERAL SIGNIFICANCE These findings represent the first and fundamental step in immune compatibility evaluation of BNNTs, mandatory before any further pre-clinical testing.

Hypergravity As a Tool for Cell Stimulation: Implications in Biomedicine

Gravity deeply influences numerous biological events in living organisms. Variations in gravity values induce adaptive reactions that have been shown to play important roles, for instance in cell survival, growth, and spatial organization. In this paper, we summarize effects of gravity values higher than that one experienced by cells and tissues on Earth, i.e., hypergravity, with particular attention to the nervous and the musculoskeletal systems. Besides the biological consequences that hypergravity induces in the living matter, we will discuss the possibility of exploiting this augmented force in tissue engineering and regenerative medicine, and thus hypergravity significance as a new therapeutic approach both in vitro and in vivo.

In vitro study on the generation of tympanic membrane substitutes via tissue engineering

The tympanic membrane (TM) is an anatomical structure with unique histological and physiological features playing a fundamental role in sound transmission. In particular, the middle layer of the pars tensa, which represents the widest and thickest surface portion of the TM, consists of connective tissue mainly composed of collagen types II and III fibers, while collagen type I is present at a lesser extent [1]. Several pathologies affect the TM, including otitis media, tympanosclerosis, cholesteatoma and perforation that require reconstructive surgery depending on the lesion extent [2]. To this purpose, the temporalis fascia is currently considered as the gold standard material. However, due to limited graft availability, fully synthetic substitutes are also applied, with poorly satisfactory outcomes. For these reasons new strategies for TM replacement are still needed. In this study, we employed a tissue engineering (TE) approach for the regeneration of TM substitutes selecting some biocompatible and bioresorbable polymeric matrices to be cultured with human bone marrow-derived mesenchymal stem cells (MSCs). We set up a cell differentiation protocol using an appropriate mix of growing factors to obtain the in vitro differentiation of MSCs into TM fibroblasts. Furthermore, because of the role played by mechanical forces in TM motion, these engineered substitutes underwent mechanical stress during the culture. The obtained biohybrid constructs were characterized about cellular viability assays, gene expression quantification as well as histochemical and immunohistochemical analyses. Moreover, native TMs from cadavers were investigated for assessment and optimization of the engineered constructs. Our results showed that MSCs were able to grow and differentiate properly on the selected biomaterials and to synthesize appropriate extracellular matrix molecules. Moreover, the applied mechanical forces seem to promote TM-fibroblastic differentiation, increasing the production of collagen type II, that is a peculiarity of TM structure.

Boron nitride nanotubes in nanomedicine: Historical and future perspectives

In this chapter we will approach the story, the on-going research, and the future perspectives of boron nitride nanotube (BNNT) applications, with particular emphasis on the biomedical field. We will review the main groups involved in BNNT research, starting from their theoretical prediction until their availability on the market. The analysis of BNNT-related patents and the mandatory steps necessary for the further development in the preclinical research will conclude our dissertation.